World-renowned Brazilian architect Oscar Niemeyer, who designed much of Brazil's modern capital, died Wednesday at the age of 104.

Niemeyer is most famous for his use of abstract forms and curves, abandoning traditional straight lines. He was among the first to explore the possibilities of reinforced concrete to convey his creative vision.

The Brazilian architect established himself during the middle of the 20th century as one of modernism's greatest visionaries. He designed hundreds of objects around the world, including work on the United Nations headquarters in New York City.

On that and other early projects, Niemeyer teamed up with another pioneer of post-war buildings in concrete, the French-Swiss architect Charles-Edouard Jeanneret-Gris, better known by his pseudonym of Le Corbusier.

In 1956, Niemeyer was appointed chief architect for Brazil's futuristic capital, Brasilia, a new city in the heart of the Amazon jungle. That achievement brought him worldwide fame.